# SCLEROTIN PRECURSORS IN DIPTERANS

> **NIH NIH R01** · UNIVERSITY OF MASSACHUSETTS BOSTON · 1989 · $263,534

## Abstract

Dipteran insects -- which are responsible for the spreading of
malaria, yellow fever, dengue fever, encephalitis and sleeping
sickness -- like other insects are protected from their
environmental enemies by their tough cuticle.  At each molting
cycle, the old cuticle is shed and a new cuticle is made to allow
growth and development of the insect.  Freshly made cuticle is
soft and pale, but soon it becomes stiffened by sclerotization
reactions involving adduct formation between cuticular proteins,
phenols and chitin.  The long term objectives is to unravel the
structure and mechanism of formation of crosslinks responsible
for the stabilization of cuticle and to understand the role of
phenoloxidase and related enzymes in sclerotization, wound
healing and melanization.  The specific aims are:  a) to study the
biochemistry of quinone methide sclerotization, b) to determine
the structure of crosslinks formed in cuticle and c) to study the
biochemistry of phenoloxidase-protease cascade in dipterans.  To
achieve these goals the following studies will be carried out:
Studies on quinone methide sclerotization, which was discovered
in this laboratory, will be continued using specifically labelled
catechols and cuticular enzymes from Sarcophaga bullata and
Aedes aegypti.  The properties of quinone methide generating
enzymes will be studied.  Inhibition spectrum by a variety of
quinones and catechols will be analyzed for vector control
measures.  The general occurrence of quinone methide
sclerotization in insects will be tested.  The structure of adducts
formed during quinone tanning and quinone methide tanning will
be determined by a combination of chemical, biochemical, and
spectroscopic techniques.  To assist characterization of natural
isolates, synthetic adducts will be made and characterized.
Quinone to beta-sclerotization ratio in destabilized mosquito
cuticle will be determined.  Model sclerotization studies will be
continued and noninvasible probes of cuticular structure by ESR
will be carried out.  These studies on prophenoloxidase-protease-
protease inhibitor cascade in S. bullata will be continued and
extended to A. aegypti.  Using appropriate antibodies, the
relationship between soluble hemolymph prophenoloxidase and the
cuticular phenoloxidase and the site of synthesis and localization
of these components will be determined.

## Key facts

- **NIH application ID:** 3125862
- **Project number:** 5R01AI014753-11
- **Recipient organization:** UNIVERSITY OF MASSACHUSETTS BOSTON
- **SAM.gov UEI:** CGCDJ24JJLZ1
- **Principal Investigator:** Manickam Sugumaran
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1989
- **Award amount:** $263,534
- **Award type:** 5
- **Project period:** 1978-08-01 → 1991-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3125862

## Citation

> US National Institutes of Health, RePORTER application 3125862, SCLEROTIN PRECURSORS IN DIPTERANS (5R01AI014753-11). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3125862. Licensed CC0.

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